• Home
• Science Strategy
• Science Teams
• Projects
  • Screening for Physical Dormancy (MSBP Collections)
• People
• Publications
• Acronyms

Screening for Physical Dormancy (MSBP Collections)

Physical dormancy in MSB Collections. Occurrence of Physical Dormancy in different plant types of Melianthus major.

This project is one of a series in the theme of 'Ecophysiology and Morphology'.

Physical dormancy (PY), defined as an inability to imbibe water because of a hard impermeable seed coat, has been reported in fifteen angiosperm families.  In routine germination testing of conservation collections the removal of PY by scarification of individual seeds is straightforward and extremely effective but also very time consuming.  Although published evidence indicates that PY is extremely common in certain families such the Fabaceae it is also clear from our own work that PY may be absent from some species and genera.  More reliable prediction of the occurrence of PY and a better understanding of the factors that influence the development of PY will improve the efficiency of germination testing and our understanding of the evolution of this trait.

Using a simple imbibition test, this project focused initially on incoming MSB collections from genera that had not been reported previously in the literature to possess PY but were within the fifteen cited families. We also targeted species outside these families, already held in the MSB, which had proven to be difficult to germinate but had shown a positive response to scarification.  Tests on 98 MSB collections so far have revealed a number of interesting findings including an absence of PY in all collections tested from the genus Brachystegia (Fabaceae-Caesalpinioideae) and the presence of PY in two families not previously reported to exhibit PY (Hernandiaceae and Labiatae).

The general screening of incoming collections will continue. However, in view of the importance of the Fabaceae (one in six of all collections held in the MSB), the project is also now focusing on all incoming collections of this family. The far greater numbers of species encountered compared to other families will enable us to analyse for correlations between the occurrence of PY and other factors such as habitat, geographical origin, aridity and climate factors and hence increase the likelihood of being able to generate a predictive model for PY.

Kew Home | Science Directory | Copyright & Privacy